One correction, the outer circle for ships with sonar (which is the only circle for ships without) is the visual range, most Japanese ships didn't have radar even late in the war.
If you're on the surface, given the conditions of ideal visibility (clear weather, calm seas, daylight) and alert lookouts (warships have better lookouts than merchants) they will see you if you're inside that outer circle. Darkness, rain, fog, heavy seas, speed, and other factors reduce the range, if you're moving slowly and flooded down to 25 feet ("decks awash") and facing directly toward or away from the target you can get much closer without being seen. Obviously if you're submerged you can't be seen.
The smaller circle for an escort is the passive sonar, the arc cut out at the back is noise interference from his own propellers - if you're behind him he can't hear your propellers, he can only hear his own. Anywhere else in that yellow area he might or might not hear you depending on how close you are and how much noise you're making, running at high speed and loading torpedoes close to him is considered "bad".
The red half circle is the active sonar, the "pings". Best way to avoid both is to go deep, when you hear
"Passing thermal layer!", go down another 50 to 60 feet below that and his pinging will bounce off the layer. Sneak away quietly, I generally use the compass tool to draw a five mile circle from point of last contact, when I'm outside that it's safe to come back to periscope depth and look around.